Alireza Mohammadzadeh - Associate Professor, Department of Microbiology, School of Medicine, Infectious Diseases Research Center, Gonabad University of Medical Sciences, Gonabad, Iran.
Ali ALAMI - Department of Public Health, Faculty of Health, Social Determinants of Health Research Center, Gonabad University of Medical Sciences, Gonabad, Iran
Bahareh Rezvani - Medical Student, Student Research Committee, School of Medicine, Gonabad University of Medical Sciences, Gonabad, Iran.
Jalal Mardaneh - Associate Professor, Department of Microbiology, School of Medicine, Infectious Diseases Research Center, Gonabad University of Medical Sciences, Gonabad, Iran.

BACKGROUND AND OBJECTIVESAntibiotic resistance in pathogens, especially Escherichia coli, has become a major treatment issue. Resistance of this organism occurs via the production of extended-spectrum β-lactamases (ESBLs). The aim of this study was to determine the prevalence of the E. coli strains producing extended-spectrum beta-lactamases (ESBLs) enzymes and their antibiotic resistance patterns.MATERIALS AND METHODSIn this descriptive study, ۲۵۵ different Escherichia coli isolates isolated from the samples of patients referred to Allameh Bohlool Hospital in Gonabad were examined. After collection, the data were entered in SPSS software version ۱۶ and analyzed using descriptive statistics tests.RESULTS AND DISCUSSIONIn this study, out of ۲۵۵ people sampled, ۸۳.۵% were female and the mean age of patients was ۳۹ ± ۳۰ year. The frequency of Escherichia coli producing ESBL (Extended spectrum beta-lactamase enzymes) was ۴۰.۷۸%. The highest susceptibility to imipenem (۸۱.۷۰%) and the highest resistance to cefotaxime (۱۰۰%) were observed. The frequency of isolates with ESBL in outpatients was ۳۴.۰۱% and inpatients was ۵۰% (P = ۰.۰۱). The number of isolates with ESBL was higher in men than women (P = ۰.۰۱۸). ۶۸.۲۶% of ESBL generating isolates had multidrug resistance and ۶۴.۴۲% had cross-resistance.CONCLUSIONThe results showed that more than ۴۰ % isolates were detected as ESBL- producing strains. Based on the observed high percentage of resistance to the third-generation-cephalosporins, it is vitally important to perform precise and accurate antibiogram. Avoiding excessive over-prescription of antibiotics for infections caused by ESBL-producing organism is an inevitable necessity.

Antibiotic resistance, Escherichia coli, Extended-spectrum beta-lactamase enzyme